java - 在android中删除位图

Question

如何在 Android 中删除位图？我创建了一个名为“太阳”的位图，但是当我完成一个人走过屏幕后，我想添加一个名为“月亮”的新位图，但它只是在太阳上方创建，我怎样才能删除太阳位图？这是我为行走的人编写的代码。

    switch (counter)
    {

    case 0:
        skyRect.set(0, 0, canvas.getWidth(), 400);
        canvas.drawRect(skyRect, sky);
        canvas.drawBitmap(AndroidDude, changingX, (canvas.getHeight()/2 - (AndroidDude.getHeight()/2)), null);
        if (changingX < canvas.getWidth())
        {
            changingX += 10;
        }
        else 
        {
            changingX = 0;
            sunChangingX = 0;
            counter++;
        }

        grassRect.set(0, 400, canvas.getWidth(), canvas.getHeight());
        canvas.drawRect(grassRect, grass);
        canvas.drawBitmap(cloud, 100, 50, null);
        canvas.drawBitmap(cloud, 700, 100, null);
        canvas.drawBitmap(sun, (canvas.getWidth() - sun.getWidth()), 0, null);
        invalidate();
        break;

    case 1:
        //Remove sun and clouds here?
        canvas.drawBitmap(moon, (canvas.getWidth() - moon.getWidth()), 0, null);
        canvas.drawBitmap(AndroidDude, changingX, (canvas.getHeight()/2 - (AndroidDude.getHeight()/2)), null);
        if (changingX < canvas.getWidth())
        {
            changingX += 10;
        }
        else 
        {
            changingX = 0;
            counter++;
        }
        grassRect.set(0, 400, canvas.getWidth(), canvas.getHeight());
        canvas.drawRect(grassRect, grass);
        canvas.drawBitmap(cloud, 100, 50, null);
        canvas.drawBitmap(cloud, 700, 100, null);
        canvas.drawBitmap(sun, sunChangingX, 0, null);
        invalidate();
        break;
    }

Answer 1

在要删除的位图上重新绘制背景(天空和草地)。做一个刷新功能。